Electron-beam devices (EBD in the following) may be used in many different fields. They may be characterized in the energy of the emitted electrons, which in turn is coupled to their intended use, such as the ones used for curing of paint or sterilization of surfaces. The present invention mainly relates to an EBD which may be used for sterilization purposes, in which the energy of the emitted electrons resides in an interval of about 50-300 keV. This should not, however, be construed as limiting, since there may be adequate applications for the present invention outside said interval too. Within the field of EBD:s used for sterilization, there are several different types, differing in size and shape, again depending on the intended use. The present invention is mainly directed towards an EBD which may be used for sterilization of a surface, or rather a web of material, and it therefore may have an elongate body and a likewise elongate cathode housing inside the elongate body. Again, the present invention should not be limited to the exact shape mentioned here, since it may also be applied to other EBD:s.
An electron gun incorporating the features according to the above description is disclosed in U.S. Pat. No. 3,863,163 to Farrell et al. Individual components of EBD:s are well described in the literature, and upon reading the present application the skilled person should have little or no problem in practising the present invention.